Here's the scoop from Korbi at E! Online, which sounds very promising.

[Korbi] ran into Chyler Leigh (aka Meredith Grey’s half sister, aka Carla on Reunion!) at TCA, and she said things may be a bit different this year: “Last season was kind of depressing, even [creator] Shonda [Rhimes] said it. She was kind of burning all the characters down, so this is kind of the redemption of all those characters. People can expect the fun Grey’s again this year.” Regarding her new series-regular status, she says she hopes to be in every episode this season. She believes that’s the plan, but you don’t really know until you get each script. She’s slowly trying to prepare herself for the instant fame the show is sure to bring. “It’s interesting, because even with just the two and a half minutes that I was on [Grey’s Anatomy] this last season, people already hate me! It’s unbelievable. I’m getting threats!” She’s thrilled to be on the Seattle Grace team, though, and is excited about her storyline: “The idea is that I’ll kind of be representing the intern world and then dipping in and out of everyone else’s storylines.”

Aww, little ol' Chyler's starting to grow on me! She seems so...Grey like. She should fit right it!